1. Field
The present disclosure relates generally to identifying interference path loss and in particular to a method and apparatus for identifying interference path loss associated with an aircraft. Still more particularly, the present disclosure relates to a method and apparatus for statistically identifying interference path loss associated with the transmission of radio frequency signals within an interior of an aircraft using discrete frequency stirring.
2. Background
In designing and manufacturing aircraft, reverberant environment measurement methods are used to identify the interference path loss of radio frequency signals from within an aircraft. The interference path loss is defined as the ratio of the radio frequency power at the aircraft communication, navigation or surveillance receiver input to the transmitted radio frequency power measured at the output of the transmitter connector at the reference antenna terminals. The ratio of radio frequency power as described is the attenuation, or path loss of the radio frequency signal from within an aircraft to the front end of the receiver as measured through an aircraft antenna located outside of the aircraft. A radio frequency signal is an example of an electromagnetic wave.
Within an aircraft, the transmit antenna is located within the interior of the aircraft. This antenna may be located in, for example, the flight deck, a passenger cabin, a galley, or some other suitable location within the aircraft. The receive antenna may take the form of an aircraft communication and/or navigation radio antenna that may be located on the exterior of the aircraft.
These measurements may be part of a process to certify that an aircraft is tolerant of portable electronic devices used onboard the aircraft. One process currently used for certifying aircraft involves moving an antenna within the aircraft and performing measurements around every 50 centimeters from the last measurement point. This process also may include changing the polarization of the antenna, as well as measuring around doors, the flight deck, and the cargo area of the interior. This type of process; however, is time consuming and may require hundreds of hours to perform the tests within guideline procedures. This type of testing is expensive. Therefore, it would be advantageous to have a method and apparatus to overcome the problems described above.